Will by a coparcener of huf

An ancestral property in Delhi has been divided amongst 4 brothers through a partition award. Then each brother had his own HUF. One brother died, leaving behind his wife and a son. Sometime later, the son died and after that, the wife has also passed away. Now, no class 1 legal heirs are there! Will the property of the dead brother comes back to the brothers, being class 2 legal heirs or if the wife has made a Will before her death and has given the property to her sister, so was she in a good legal position to do it?